Résumé Drought is the major climatic phenomenon that affects the semi-arid region of Northeast Brazilon a recurring basis, with extreme negative consequences on water availability, resulting in environmental, economic, social and cultural catastrophes. Drought indices are tools that aid decisions of public managers, guiding actions to effectively reach the affected population. Generally, indices used in Northeast Brazil are based solely on meteorological or hydrological data, with the exception of the FUNCEME1s Drought Severity Index (FDSI), created by FundaÃÃo Cearense de Meteorologia, in 2000, that was not implemented due to operational difficulties. Therefore, there is a lack of an index that allows a better understanding of the phenomenon, using available and reliable data, and that can be easily manipulated. The objective of this thesis was to construct an Index of Susceptibility to Drought (ISD), which considers not only climatic data, but also soil, economic and social aspects, plus risks of harvest loss and shortage of human and animal drinking water. The ISD was constructed following the method proposed byJRC/OECD, using techniques for multiple imputation and data winsorization. It was tested and validated with real data from a11 Rio Grande do Norte municipalities, in three climatic scenarios : dry, normal and wet years. The ISD classification of the municipalities and the consistency of the weights adopted in the ISD construction were validated with a sensitivity analysis, using Monte Carlo simulations. Software written in C Sharp and composed of eight modules was developed to obtain and operate the ISD. This applicative uses on R and has import and data entry facilities, performs statistical calculations, and generates maps and reports